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Open arteries

ONE-third of people who have surgery to clear arteries blocked with plaque
need follow-up surgery within six months to clear further blockages. But a
technique that uses laser light and a photosensitising chemical could make
repeat surgery unnecessary.

The most commonly used method for clearing blockages is balloon angioplasty,
in which a small balloon is inflated inside the artery. “Unfortunately the
treatment can stimulate the proliferation of smooth muscle cells in the artery
wall and they can end up causing another blockage within six months,” says
Stephen Bown, director of the National Medical Laser Centre at University
College London. The process, an inflammatory response to the clearing of the
blockage, is called restenosis.

Bown’s team tried a laser-based therapy in seven patients who needed a second
balloon angioplasty. Before the procedure, the subjects were given the drug
5-amino laevulinic acid, which sensitises tissue to breakdown by laser light.
Immediately after angioplasty, a thin optical fibre inserted into the artery
delivered low-power red laser light to the site, killing the smooth muscle
cells. Six months later, treated arteries remained clear in all seven
patients.

“The smooth cells do grow back, but very slowly,” says Bown, who presented
his findings to the annual meeting of the Association of Surgeons of Great
Britain and Ireland this week in Brighton. A bigger study with patients who are
having their first angioplasty will start in the autumn.